The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
3GPP Third Generation Partnership Project
A/N: ACK/NACK Acknowledgement/Negative Acknowledgement
CoMP Coordinated Multi-Point
CQI Channel Quality Indicator
CRS Common (Cell-specific) Reference Signals
CSI Channel State Information
CSI-RS Channel State Information Reference Signals
DL Downlink
DM RS Demodulation Reference Signal
E-UTRA Evolved Universal Terrestrial Radio Access
eNB Evolved Node B/Base Station in an E-UTRAN System
E-UTRAN Evolved UTRAN (LTE)
FDD Frequency Division Duplex
FDM Frequency Division Multiplexing
ID (id) Identity/Identification
LTE Long Term Evolution
LTE-A Long Term Evolution Advanced
MAC Medium Access Control
PC Power Control
PCell Primary Cell
PHY Physical Layer
PL Path Loss
PRB Physical Resource Block
PDCCH Physical Downlink Control Channel
PUCCH Physical Uplink Control Channel
PUSCH Physical Uplink Shared Channel
RRC Radio Resource Control
RAN Radio Access Network
RRH Remote Radio Head
Rx Reception
SC-FDMA Single-Carrier Frequency Division Multiple Access
SCell Secondary Sell
SINR Signal-to-Interference-Plus-Noise Ratio
TDD Time Division Duplex
TDM Time Division Multiplexing
TPC Transmitter Power Control
Tx Transmit
UCI Uplink Control Information
UE User Equipment (e.g. mobile terminal)
UL Uplink
UL-SCH Uplink Shared Channel
UTRAN Universal Terrestrial Radio Access Network
Coordinated Multi-Point (CoMP) transmission and reception is one of the technologies investigated in 3GPP. During the study, an uplink power control was recognized as one of the topics where enhancements need to be considered.
In Release 10 of 3GPP, PUCCH PC is defined by the formula (see 3GPP TS 36.213 V10.3.0 (2011-09), Section 5.1.2.1) as follows:
                                                        P              PUCCH                        ⁡                          (              i              )                                =                      min            ⁢                          {                                                                                                                                            P                                                      CMAX                            ,                            c                                                                          ⁡                                                  (                          i                          )                                                                    ,                                                                                                                                                          P                                                  0                          ⁢                                                      _                            ⁢                            PUCCH                                                                                              +                                              PL                        c                                            +                                              h                        ⁡                                                  (                                                                                    n                              CQI                                                        ,                                                          n                              HARQ                                                        ,                                                          n                              SR                                                                                )                                                                    +                                                                        Δ                          F_PUCCH                                                ⁡                                                  (                          F                          )                                                                    +                                                                        Δ                                                      T                            ×                            D                                                                          ⁡                                                  (                                                      F                            ′                                                    )                                                                    +                                              g                        ⁡                                                  (                          i                          )                                                                                                                                }                                      ,                            (        1        )            
where Po_PUCCH parameter defines the signal power level at the reception. PL_c is the pathloss (open loop component) based on CRS measurement in the downlink, and g(i) is the accumulated value of closed loop power control commands. The rest of the parameters are used to scale power so that different number of control bits, different number of antennas and different PUCCH formats are taken into account.
Also a similar expression is provided for the PUSCH PC (see 3GPP TS 36.213 V10.3.0 (2011-09), Section 5.1.1.1) as follows:
                                          P                          PUSCH              ,              c                                ⁡                      (            i            )                          =                  min          ⁢                                    {                                                                                                                                            P                                                      CMAX                            ,                            c                                                                          ⁡                                                  (                          i                          )                                                                    ,                                                                                                                                  10                      ⁢                                                                                          ⁢                                                                        log                          10                                                (                                                                                                            M                                                              PUSCH                                c                                                                                      ⁡                                                          (                              i                              )                                                                                +                                                                                    P                                                              O_PUSCH                                ,                                c                                                                                      ⁡                                                          (                              j                              )                                                                                +                                                                                                                    α                                c                                                            ⁡                                                              (                                j                                )                                                                                      ·                                                          PL                              c                                                                                +                                                                                    Δ                                                              TF                                ,                                c                                                                                      ⁡                                                          (                              i                              )                                                                                +                                                                                    f                              c                                                        ⁡                                                          (                              i                              )                                                                                                                                                                                      }                        .                                              (        2        )            
There are several issues that need to be taken into account when defining PUCCH (or PUSCH) PC operation for the CoMP case.